An excavator works at a Rio Tinto coal mine in the Hunter valley, north of Sydney, Australia. Photograph: Ho/Reuters

Thought Shell's cash flows were impressive? Wait until you see what the miners are doing. The price of copper touched $10,000 a tonne today. The cost of production for the likes of BHP Billiton and Rio Tinto is about $2,500. Similarly, some iron ore can be dug up at a cost of $20 a tonne in Australia. Freight costs are about $10 to China, where customers pay $160. Right now, mining is even hotter than oil.